I was doing a talk on canine and feline infectious diseases in shelter environment yesterday evening, and as usual, I like to ask questions to the audience (good way to see if they can stand my Franglish right?). This is one of my favourite: do you know what is the difference between cleaning and disinfecting? Interesting to see the look in the eyes of people at this very moment: you can see them wondering why I am asking what they usually consider as “such a basic question”. Never got anything else than a big YES as an answer… But then I followed up and asked my second question (because it’s all part of a plan, right?): what are you using as a cleaner? First answer: bleach. Perfect counter-example, my demonstration was made!!! Bleach is indeed an excellent disinfectant, but when it comes to pure cleaning, its something you should definitely avoid doing…

Getting lost? Ok, let’s start again from the beginning!

Cleaning: making something free of dirt, which means removing the organic matter (feces for instance). When you clean, your target is physical cleanliness.

Disinfecting: destroy or prevent the growth of disease-carrying microorganisms. You’re now targeting the germs remaining in the environment; your goal is to obtain bacteriological cleanliness.

Why is it so important? Because you cannot clean AND disinfect at the same time, this always needs to be a two-step process! Bleach for instance is a very good disinfectant, but if you use it to clean, it will be inactivated in the presence of organic matter. So again if you are using bleach as a cleaner, which is an improper use of the product, plenty of germs are still in the environment when you think you’re done. You feel like you’re protected, while in fact, this is absolutely not the case… Look at the following figure, here are the different mandatory steps of the process!

And what about those products that claim to “clean and disinfect”? Well, some of them indeed do have some detergent activity (this is the case for quaternary ammoniums or accelerated hydrogen peroxide) but again, if you read carefully the labels, it is clearly written: this two-step procedure is always needed (even if you use the same product, first you clean, then you rinse, then you disinfect).

So it’s important to make this clear with your staff: they must not cut corners in the cleaning and disinfecting protocol. It is important to clearly follow the rules to make the process fully efficient: respecting the adequate concentrations (for instance bleach will destroy parvovirus when diluted at 1:32 while to inactivate ringworm, you’ll need to do it a 1:10!) and the contact length (most of the disinfectant will need to remain 10 minutes on the surfaces to be fully efficient, new disinfectants need 1-5 minutes and no further rinsing is needed, but there are more expensive then!).

It’s never a loss of time to educate your staff and volunteers on these basic topics. Despite all their good will, they might not see how important it is if not educated properly. Keep in mind we have dedicated training modules on the topic that we propose to our shelter partners. An educated staff will definitely make your life easier!

Remember we are all part of the same PRO community! Don’t hesitate then: share with us your experiences, ask your questions and let us know what you think! Social networks enable us to keep the discussion going, so whether you are a Facebooker or a Twitter-addict, you can – and should!- be part of it!

Thanks Emmanuel. Your talk opened my eyes to new possibilities, that what I was doing wasn't quite right. If I change my technique of cleaning it might cut down on the passing of viruses and infections.

Interesting comment, thanks! In fact, the dishwasher is a specific case, No need for bleach here in my opinion, the rinsing phase is usually at +82degrees C which will do the trick here in terms of disinfection. This should be ok if the dishes are not soiled with organic matter before being put in the dishwasher (a pre-rinsing to remove anything that sticks to the bowl should be enough).

If there was no dishwasher however, I would recommend to do what you wrote in your comment (cleaning first, rinsing and then disinfecting for at least 10 minutes -depending on the disinfectant that is used). Hope this will help!

You make a very interesting point. I am part of a group of home-based animal shelter. I put some bleach in the dishwater thinking I was disenfecting at the same time I do the cats' dishes as well as wash the counters and all level areas the cats hang out on. Therefore having read your article, I am assuming that after washing the dishes I should be putting the dishes in a rinse bath that contains a disinfectant for 10 minutes ( at what a ratio should I use for just general disinfecting?)then rinse again and then dry. Did I get it right?